This invention relates to a method of making roofing shingles. More particularly, this invention relates to a method of improving the synchronization between blend drop and cutting of roofing shingles.
The use of aesthetically pleasing roofing shingles is popular among consumers. Aesthetically pleasing roofing shingles are produced by varying the pattern of colors in the shingles as well as their length, and spacing between their tabs, cutouts, and notches. The color of shingles can be varied by placing colored granules in patterns at specified locations with respect to the patterns of cuts, such as length cuts and tab cuts, in the shingles. Color patterns which are misplaced at undesirable locations with respect to the tabs, cutouts, and notches in the shingles produce poor quality shingles. Thus, it would be desirable to produce a method of synchronizing the placement of the color patterns with respect to the tabs, cutouts, and notches in the shingles.
The above objects as well as other objects not specifically enumerated are achieved by a method and apparatus to synchronize the blend drop and cutting of roofing shingles. The method and apparatus include providing a continuous shingle mat coated with roofing asphalt. The mat is covered with granules to form a continuous granule covered sheet. A series of timing marks are placed on the continuous granule covered sheet. A rotary pattern cutter cuts a pattern of tabs and cutouts in the continuous granule covered sheet. The rotary position of the pattern cutter and the position of the timing marks are sensed. The position of the continuous granule covered sheet with respect to the rotary position of the pattern cutter is synchronized in response to the sensed position of the timing marks and the sensed rotary position of the pattern cutter. The continuous granule covered sheet is cut with the pattern cutter. The apparatus preferably includes an applicator for placing a series of timing marks on the continuous granule covered sheet and a photoeye for sensing the position of the timing marks. Accordingly the method and apparatus provide improved synchronization between the blend drop and cutting of the roofing shingles.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.